Hydrocurable ambient curing polyepoxide coating and adhesive compositions and method of using same

ABSTRACT

Resin-forming polyepoxides are mixed with polyoxazolidinyl compounds or polymers containing pendant oxazolidinyl groups in which the carbon atom in the 2-position of the heterocyclic ring is substituted with saturated hydrocarbon groups, such as dialkyl, or with an alkylene group forming a saturated ring with the carbon atom in the 2-position of the oxazolidinyl ring to form, in the absence of water, a stable composition which can be stored in closed containers for months without undergoing gelation. When such compositions are spread into films and the films exposed to moisture at ambient temperature, e.g., to ambient air having a relative humidity of at least 20% and temperature of about 15° to 25° C., the polymer serves to react with and cure the polyepoxide.

BACKGROUND OF THE INVENTION

This invention relates to coating, impregnating, and adhesivecompositions of a resin-forming polyepoxide mixed with a polyfunctionalcompound containing cyclic oxazolidinyl groups.

Polyepoxides, such as, for example, those obtained by reactingepichlorohydrin with polyhydric phenols in the presence of caustic, arepromising materials for use in many industrial applications as they canbe reacted with curing agents to form insoluble infusible productshaving good chemical resistance. The conventional polyepoxide-curingagent systems, however, have a drawback that greatly limits theindustrial use of the polyepoxides. The known mixtures comprising thepolyepoxide and curing agent set up rather rapidly, and this is trueeven though the mixtures are stored in air-tight containers away frommoisture and air and even though the temperature is maintained quitelow. This difficulty necessitates a mixing of the components just beforeuse and a rapid use of the material before cure sets in. Such aprocedure places a considerable burden on the individual operators, andin many cases, gives inferior products resulting from inefficient mixingand too rapid operations.

Numerous attempts have been made to provide a latent curing agent forpolyepoxides, by which is meant the type of resin-forming organiccompound containing a plurality of vic-epoxy groups of the formula##STR1##

Such compounds may be saturated or unsaturated, aliphatic,cycloaliphatic, aromatic, or heterocyclic and may be substituted, ifdesired, with substituents such as chlorine atoms, hydroxyl groups,ether radicals, and the like.

Holm, U.S. Pat. No. 3,291,775 and Gardner and Keough, U.S. Pat. No.3,547,886 disclose the use of certain polyimines obtainable by reactinga ketone or aldehyde with a polyamine to cure or resinify a polyepoxide.

Hankins and Emmons, U.S. Pat. No. 3,037,006, disclose that copolymers of5 to 25% by weight of an N-(acryloxyalkyl)-oxazolidine or anN-(acryloxyalkyl)tetrahydro-1,3-oxazine embraced by the formula ##STR2##where n is an integer having a value of 1 to 2,

m is an integer having a value of 2 to 3,

R¹, when not directly joined to R², is selected from the groupconsisting of hydrogen, phenyl, benzyl, and C₁ -C₁₂ alkyl groups,

R², when not directly joined to R¹, is selected from the groupconsisting of hydrogen and C₁ -C₄ alkyl groups and

R¹ and R², when directly joined together, form a 5- to 6-carbon ringwith the attached carbon atom of the ring in the formula, i.e., R¹ and

R², when joined together, are selected from the group consisting ofpentamethylene and tetramethylene,

can be mixed with polyepoxides for the production of insoluble andinfusible crosslinked coatings. There is no suggestion in this patentthat the copolymers in which R¹ and R² are independent saturatedhydrocarbon groups or together an alkylene group forming a 5- to6-carbon ring with the attached carbon of the ring in the formula wouldprovide distinctive and unexpected storagestability properties that arelacking in those copolymers in which either or both R¹ and R² is, orare, hydrogen atoms. R¹ and R² are attached to the 2-position carbon inthe heterocyclic ring of the formula.

DESCRIPTION OF THE INVENTION

It is an object of the invention to provide a new class of latent curingagents for polyepoxides. It is a further object to provide new curingagents for polyepoxides that are substantially unreactive withpolyepoxides when stored under atmospheres substantially free ofmoisture. It is a further object to provide new curing agents that canbe premixed with the polyepoxides and the mixture stored or shippedwithout danger of premature gelation. It is a further object to providenew compositions containing polyepoxides that undergo cure only when incontact with moisture. It is a further object to provide a new processfor curing polyepoxides that is particularly useful for the preparationof surface coatings. It is a further object to provide new curing agentsfor polyepoxides that may be cured to prepare high solids orsolvent-free coatings. These and other objects of the invention will beapparent from the following detailed description thereof.

In accordance with the present invention, it has been discovered that"one-pot" coating compositions based on a polyepoxide can be preparedwith a polyfunctional compound or polymer containing a plurality ofpendant 2,2-dialkyl-oxazolidinyl or 2,2-alkylene-oxazolidinyl groups ofthe formula ##STR3## where m is an integer having a value of 2,

R¹ and R² are individual alkyl groups, e.g. having 1 to 12 carbon atoms,or together may be a pentamethylene or tetramethylene group forming a 5-to 6-carbon ring with the attached carbon of the ring in the formula,

or the analogous 2,2-dialkyl- or 2,2-alkylene-tetrahydro1,3-oxazinylgroups of the formula IA where m is 3. These groups are genericallyreferred to hereinafter as cyclic oxazolidinyl groups.

It has been discovered that the polyepoxide may be mixed with apolyfunctional compound or a vinyl addition or condensation polymercontaining a plurality of pendant (and/or terminal) cyclic oxazolidinylgroups of Formula IA in the absence of water and formulated withconventional non-aqueous ingredients, such as pigments, fillers,dispersing agents, and rheological agents to prepare coatingcompositions that can be packaged in closed containers in the absence ofmoisture and stored therein for extensive period of time withoutreaction between the polyepoxide and the compound or polymers containingthe pendant oxazolidinyl groups of Formula IA. However, when thecomposition is subsequently spread out and exposed to moist atmoshere,the composition sets up or cures even at ambient temperature (of about15° to 25° C.) to form a hard, infusible film.

The poly(formula IA cyclic) compound may be obtained in any of severalways. An N-hydroxyalkyl-2,2-dialkyl- or 2,2-alkylene compound having acyclic group of Formula IA may first be prepared by reactingdiethanolamine or dipropanolamine with a dialkylketone, or acyclopentanone or cyclohexanone. The resulting cyclic oxazolidinylcompound can then be converted into a poly(ester) by using it totransesterify a polyester of a polycarboxylic acid, such asdimethyladipate, dimethylsuccinate, and so on. The resultingpoly(IA)cyclic compound is effective as a curing agent for a polyepoxidewhen mixed therewith and then applied, in the mixture, for coating,impregnating, or binding in the presence of moisture. It is essentialthat there be no other amine nitrogen groups in the polyfunctionalcompound containing the cyclic IA groups.

Similarly the N-hydroxyalkyl cyclic oxazolidinyl compound may be reactedwith a polyisocyanate, such as a diisocyanate or triisocyanate. Then,the resulting product may be mixed with the polyepoxide in the absenceof moisture, in which condition it remains effectively stable for monthsbut upon spreading out the composition in the form of a film andexposing the latter to water or atmospheric moisture, the composition iscured or crosslinked to an infusible and insoluble condition.

The vinyl addition polymers containing the pendant groups of formula IAare preferably copolymers of the 2,2-dialkyl- or 2,2-alkylene-monomersof formula I above with at least one other monoethylenically unsaturatedcopolymerizable monomer of non-ionic nature having a group of theformula H₂ C═C<, such as styrene, vinyl toluene, acrylonitrile, and C₁to C₁₈ alkyl esters of acrylic acid or methacrylic acid, e.g., methyl,ethyl, butyl, cyclohexyl, and 2-ethylhexyl (meth)acrylate. The copolymermay contain as little as 5% by weight of the monomer of formula I up toas much as 70% by weight thereof, but preferably from about 20% to about35% by weight thereof. It is essential, however, that all of the monomerof Formula I present in the copolymer consist of the 2,2-dialkyl or2,2-alkylene substituted groups defined by formula IA above. Of thesemonomers, the preferred ones are the 2,2-dialkyl-oxazolidinylethyl(meth)acrylate.

The copolymers may be prepared by solution (organic solvent)polymerization as hereinafter described in Example IA).

The polyepoxides and poly(functional) compounds or vinyl additioncopolymers having pendant formula IA groups may be mixed in a wide rangeof proportions. In general, however, the amount of poly(functional)compound or copolymer used should provide approximately one equivalentof amine (developed in contact with water or moisture in the ambientair) for each equivalent of epoxy group. Depending on the particularcomposition or use, the ratio of amine/epoxy equivalency may vary fromabout 4:1 to about 1:4 or possibly even over a wider range in someinstances. As used herein, the equivalent amount of poly(functional)compound or copolymer is that amount needed to furnish one aminohydrogen upon hydrolytic opening of the formula IA ring to produce agroup of the formula --N(H)--(CH₂)_(m) --OH (herein designated formulaIB) with liberation of a ketone R¹ R² C═O.

In preparing the mixtures of the present invention, it is sometimesdesirable to have the polyepoxide in a mobile liquid condition when thepoly(IA)compound or polymer is added so as to facilitate through mixing.The polyepoxides as described below are generally viscous to solidmaterials at ordinary temperature. With those that are liquid, but tooviscous for readily mixing, they are either heated to reduce thevisocisty or have a liquid solvent added thereto in order to providefluidity. Normally, solid members are likewise either melted or mixedwith a liquid solvent. Various solvents are suitable for achievingfluidity of the polyepoxides. These may be volatile solvents whichescape from the mixed compositions by evaporation before or during thecuring such as ketones like acetone, methyl ethyl ketone, methyln-propyl ketone, methyl isobutyl ketone, isophorone, etc., esters suchas ethyl acetate, butyl acetate. Cellosolve® acetate (ethylene glycolmonoacetate), methyl Cellosolve acetate (acetate of ethylene glycolmonomethylether), etc.; ether alcohols such as methyl, ethyl or butylether of ethylene glycol or diethylene glycol; chlorinated hydrocarbonssuch as trichloropropane, chloroform, etc. To save expense, these activesolvents may be used in admixture with aromatic hydrocarbons such asbenzene, toluene, xylene, etc., and/or alcohols such as ethyl, isopropylor n-butyl alcohol. Solvents which remain in the cured compositions mayalso be used, such as diethylphthalate, or liquid monoepoxy compoundsincluding glycidyl allyl ether, glycidylphenyl ether, styrene oxide, andthe like, as well as cyano-substituted hydrocarbons, such asacetonitrile. It is also convenient to employ a glycidyl polyether ofthe dihydric phenol in admixture with a normally liquid glycidylpolyether of a polyhydric alcohol.

The polyepoxides to be used in the process of the invention includethose organic compounds containing a plurality of epoxy groups, i.e.,groups of the formula ##STR4## These compounds may be saturated orunsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic and maybe substituted if desired with substituents, such as chlorine atoms,hydroxyl groups, ether radicals, and the like. They may also bemonomeric or polymeric.

For clarity, many of the polyepoxides and particularly those of thepolymeric type have been defined in terms of epoxy equivalent value. Themeaning of this expression is described in U.S. Pat. No. 2,633,458.

If the polyepoxide material consists of a single compound and all of theepoxy groups are intact, the epoxy equivalency will be integers, such as2, 3, 4 and the like. However, in the case of the polymeric typepolyepoxides many of the materials may contain some of the monomericmonoepoxides and/or contain macromolecules of somewhat differentmolecular weight so the epoxy equivalent value may be quite low andcontain fractional values. The polymeric material may, for example, haveepoxy equivalent values, such as 1.5, 1.8, 2.5, and the like.

Various examples of polyepoxides that may be used in the process of theinvention are given in U.S. Pat. No. 2,633,458 and it is to beunderstood that so much of the disclosure of that patent relative toexamples of polyepoxides is incorporated by reference into thisspecification.

A group of polyepoxides which are not specifically illustrated in theabove patent but are of particular value are those which containterminal epoxy groups of the formula ##STR5## and include glycidylpolyethers of polyhydric phenols or polyhydric alcohols. These preferredresin-forming polyepoxides may be termed "ethoxyline" resins and aremore particularly defined as organic compounds free of functional groupsother than hydroxyl and epoxy groups which contain at least 2 vic-epoxygroups in which the oxygen is attached to adjacent singly-bonded carbonatoms and which have a molecular weight in the range of about 250 to5,000. The polyepoxides having epoxy equivalencies from 100 to 1,025have generally been found useful. Those having greater epoxyequivalencies up to about 1500 or higher may be used when special careis taken to select the comonomer(s) of the formula IA copolymer as wellas the proportion(s) thereof relative to polyepoxide, to provide mutualcompatibility.

Polyepoxides that may be used include the "ethoxylene resins" availableunder the tradenames of D.E.R., D.H.R., Epon, Eponex, or Aralditeresins. They include polyether derivatives of polyhydric phenolcontaining epoxy groups and may be prepared by effecting reactionbetween epichlorohydrin and a polyhydroxy phenol or alcohol, such asBis-Phenol A, or the completely hydrogenated product of Bis-Phenol A.

There may also be used as the polyepoxide component addition copolymersof glycidyl acrylate, glydicyl methacrylate, glycidyl vinyl ether, orglycidyl vinyl sulfide with other monoethylenically unsaturatedcomonomers containing a group of the formula H₂ C═C< such as a C₁ -C₁₈alkyl ester of acrylic acid or methacrylic acid, styrene, vinyl acetate,acrylonitrile, and vinylchloride. The copolymers may contain up to 40%by weight of one or more of the glycidyl esters of ethers, andpreferably contain about 10% to 30% by weight thereof.

The vinyl copolymerization system just mentioned may be used toincorporate both components in a single polymeric compound. By includingin the comonomers a 2,2-dialkyl-oxazolidinylalkyl (meth)acrylate or a2,2-alkylene analogue, a copolymer of an unsaturated glycidyl-containingmonomer with the formula IA-containing unsaturated oxazolidinyl monomersdefined hereinabove may be produced under anhydrous conditions so thatupon spreading the copolymer as a coating or adhesive and subjecting thelatter to moisture, the pendant oxazolidinyl cyclic groups hydrolyze toform secondary amine groups in the copolymer chain which cure thevic-epoxy groups therein. The copolymers contain about one equivalent oflatent amine for each equivalent of epoxy therein.

In the following examples which are illustrative of coating and adhesiveembodiments of the present invention, the parts and percentages are byweight and the temperatures are in Celsius degrees unless otherwisenoted.

EXAMPLE I Preparation of a MEOXEMA Copolymer and a Crosslinked Coatingwith it and a resin-forming Polyepoxide (A) 2-Ethyl-3;L-(2-hydroxyethyl)-2-Methyl-Oxazolidine (MEHEOX)

A mixture of 315 g (3 mols) of diethanolamine, 432 g (6 mols) ofmethylethylketone, and 100 ml of cyclohexane is stirred and heated toreflux using a Dean-Stark trap to separate the water formed. The mixtureis stirred and refluxed for a total of 311/2 hours during which 54 ml ofaqueous layer, 85% water and 15% methyl ethyl ketone by NMR, iscollected (85% of the theoretical amount of water of reaction). Themixture is then concentrated and the residue distilled to give 373 g(78% yield) of product (MEHEOX), b.p. 85°-88° C./2.5-3.0 mm Hg.

(B) Methacrylate of MEHEOX (MEOXEMA)

A mixture of 2800 g (28 mols) of methyl methacrylate, 1114 g (7 mols) of2-ethyl-3-(2-hydroxyethyl)-2-methyl-oxazolidine (MEHEOX), 20 g ofhydroquinone and 17.5 g (0.07 mol) of dibutyltin oxide is stirred andheated while a slow stream of dry air is passed thru the mixture. Thevapor is fractionated using a 10-stage Oldershaw column equipped with anisothermal distillation controller set for 50% takeoff below 65° C. and100% reflux when the temperature exceeds 65° C. After three hours, 83%of the theoretical amount of methanol has been collected and aprecipitate begins to form in the reaction mixture. The mixture iscooled to room temperature and filtered. The solid is washed with methylmethacrylate and air-dried to give 8.5 g of a tan powder which contains42% tin by elemental analysis. Excess methyl methacrylate is strippedfrom the filtrate and 1326 g of a mixture of product and2-ethyl-3-2(2-hydroxyethyl)-3-methyl-oxazolidine is distilled from theflask. This crude product is inhibited with 10 g of hydroquinone andredistilled thru an eight-inch Vigreaux column, again using an airsparge, to give 1007 g (63% yield) of product, b.p. 107°-109° C./1.8-2.0mm Hg.

(C) Copolymer of Styrene and MEOXEMA (57.88/42.11)

To 250 g of xylene, maintained at reflux (138° C.) is added continuously(dropwise) over a period of 4 hours a solution of 289.43 g of styrene,210.57 g of MEOXEMA and 6.67 g of a 75% solution of t-butyl peracetatein mineral spirits (available commercially under the trademarkdesignation Lupersol® 70). The polymerizing solution and the feedsolution of monomers and catalyst may both be sparged continuously withdry nitrogen during the 4-hour period of addition.

When the addition is completed, heating is continued for 0.5 hour. Thenan additional charge of 0.67 g of Lupersol 70 is added and heating atreflux is continued for 1 hour before cooling the completed resin toambient temperature.

(D) Coating with a Polyepoxide

To 10.0 g of the copolymer prepared in Part C is added 5.00 g ofethoxyethanol acetate and 4.40 g of a 50% solution of Epon® 828*dissolved in ethoxyethanol acetate. After mixing, a 5 mil wet film iscoated on a phosphatized steel panel (Bonderite® 1000). After 2 weekscuring at 70° F./50% RH, the KHN is 17.6 and reverse impact greater than10 in-lbs. Heating at 140° F. for 24 hrs. increases the KHN to 19.6 andthe reverse impact to more than 150 in-lbs. Chemical resistance of thecoating is excellent both before and after heating.

EXAMPLE II Preparation of a 2,2-Dialkyloxazolidinyl FunctionalPolyurethane and Coating with Polyepoxy Resins

(A) A solution of 44.2 g (0.1 mole N═C═O) of an isocyanate terminatedpolyurethane prepolymer (available commercially under the trademarkdesignation Spenkel® P-49-60CX) and 15.9 g (0.1 mole) of2-ethyl-3-(2-hydroxyethyl)-2-methyl-oxazolidine is prepared in a tightlystoppered bottle and held at ambient temperature for 24 hours. Theviscous product is dissolved in 60.0 g of anhydrous butyl Carbitol®.This solution (II-A) contains 0.76 MEq/g of amine by titration inglacial acetic acid with perchloric acid using crystal violet indicator.

(B) To 15.0 g (11.4 MEq) of Solution II-A there is added 2.0 g (11.4MEq) of Epon 828 and after thorough mixing, a coating is prepared on aBonderite 1000 test panel at a 5-mil wet film thickness. After curingunder ambient conditions (7 days/25° C., 1 day/60° C.) the film isswelled but not dissolved by methylene chlorine (MDC) and is notaffected by two hours exposure to cheese cloth patches wet with 10%aqueous acetic acid and tolune. Coating solution in a stoppered bottleis fluid after nearly 3 months storage at ambient temperature.

EXAMPLE III Preparation of thetri-2[3(2-ethyl-2-methyl-oxazolidinyl)]-ethyl carbamate of 1,6-hexanediisocyanate trimer (A) Oxazolidine Component

A solution of 19.9 g (0.125 mole) of2-ethyl-3-(2-hydroxyethyl)-2-methyl-oxazolidine, 26.6 g (0.125equivalents N═C═O) of a 75% solution of 1,6-hexamethylene-diisocyanatetrimer (available under the trademark Desmodur N) in Cellosolve acetate,and 42.2 g of toluene is heated at 95° C. for 11 hours. After cooling toroom temperature, the solution (III-A) is filtered and found to contain1.44 MEq/g of amine by titration.

(B) Coating with Polyepoxide

To 10.0 g (1.44 MEq) of the polymer Solution III-A is added 2.45 g ofEpon 828, and after mixing, a coating (5 mils wet) is prepared on aBonderite 1000 panel. After curing 7 days/25° C., 1 day/60° C. a tackfree, clear, tough film is obtained that is unaffected by exposure atambient temperature, to patches of cheesecloth saturated with 10% aceticacid and toluene, for 2 hours.

EXAMPLE IV Dialkyloxazolidinyl Diester and a Coating Prepared from itand a Polyepoxide (A) Diester

In a 500-ml three-necked flask, fitted with a stirrer, nitrogen spargingthe tube and a mirrored, vacuum jacketed, sieve plate fractionationcolumn with reflux condenser and a proportionally timed distillationtake-off mechanism, a solution of 125 g of toluene, 79.6 g (0.5 mole) of2-ethyl-3-(2-hydroxyethyl)-2-methyloxazolidine, 43.8 g (0.25 mole) ofdimethyl adipate, and 0.27 g (0.005 mole) of sodium methoxide is heatedat reflux for 6 hours. During this time methanol/toluene azeotropeboiling at 65° C. is collected yielding a total distillate weighing 26.2g corresponding to 15.8 g of methanol (99% of theory). Two successiveadditional charges of 0.30 g of sodium methoxide are added to therefluxing solution during this 6 hour period.

Upon cooling to room temperature the solution is filtered to removeinsoluble catalyst residues. The clear filtrate (IVA) contains 4.3 MEq/gamine.

(B) Coating

To 10.0 g (43.0 MEq) of the solution prepared in Part IV-A is added 7.3g (43.0 MEq) of Epon 828. After mixing, a 5 mil wet film coating isprepared on Bonderite 1000. After curing for 7 days/25° C., 1 day/60° C.a tack free, clear, tough coating is obtained which is swelled but notdissolved by methylene chloride and which is unaffected by exposure for2 hours to cheesecloth patches saturated with 10% aqueous acetic acidand toluene.

EXAMPLE V Polymer Containing Both Epoxy and DialkyloxazolidinylFunctionality and a Coating From It (A) Polymer

To 300 g of refluxing xylene, sparged with dry nitrogen gas, there isadded over a period of 4 hours, a solution of 90.44 g of methylmethacrylate (MMA), 129.06 g of butyl methacrylate (BMA), 48.23 g of2-(2,2-dimethyloxazolidinyl) ethyl methacrylate (DMOXEMA), 32.27 g ofglycidyl methacrylate (GMA), and 8.00 g of Lupersol 70. When theaddition is complete the solution is maintained at reflux for 0.5 hours,then, 0.80 g of Lupersol 70 is added and refluxing is continued for 1.0hour, before cooling to room temperature. The solution (V-A) is strawyellow and clear. The monomer components of this polymer are in themolar ratio of 4/4/1/1//MMA/BMA/GMA/DMOXEMA.

The solution (V-A) of poligomer appears unchanged after 4.5 monthsstorage in a stoppered bottle at ambient temperature.

(B) Coating

A clear coating of (V-A) is cast as a 6-mil wet film on Bonderite 1000.The coating is tack-free after 15 min. at ambient temperature. Aftercuring 18 days at ambient temperature the coating is swelled bymethylene chloride; it shows slight blistering and haze when exposed for1 hour to a cheesecloth patch saturated with 10% aqueous acetic acid; itis not attacked by 10% sodium hydroxide solution, and is only slightlyswollen by gasoline and methanol after 1 hour.

EXAMPLE VI

(A) Part (A) of Example I is a process for making MEHEOX, i.e.,2-ethyl-3-(2-hydroxyethyl)-2-methyloxazolidine by reaction ofdiethanolamine with methyl ethyl ketone. Replacement of the latterketone with acetone in molarly corresponding amount yields3-(2-hydroxyethyl)-2,2-dimethyl-oxazolidine, herein referred to by theacronym DMHEOX, i.e., dimethyl-hydroxyethyloxazolidine. Replacement ofthe ketone with cyclopentanone or cyclohexanone yields3-(2-hydroxyethyl)-2,2-tetramethylene- or3-(2-hydroxyethyl)-2,2-pentamethylene-oxazolidine.

For comparison purposes, isobutyraldehyde is used in place of the ketoneso that the reaction with diethanol amine produces3-(2-hydroxyethyl)-2-isopropyl-oxazolidine (IPHEOX) in which only one ofthe hydrogens on the 2-carbon position of the oxazolidinyl ring isreplaced with an alkyl group. Likewise, 3-(2-hydroxyethyl)-oxazolidine(HEOX) is obtained when formaldehyde is used instead ofisobutyraldehyde.

(B) The procedure of Part (B) of Example I is used to prepare theacrylate (using methyl acrylate instead of methyl methacrylate) or themethacrylate of the various 3-(2-hydroxyethyl)-oxazolidines mentioned inPart (A) hereof. The methacrylate of HEOX is referred to simply by theacronym, OXEMA; the methacrylate of IPHEOX is referred to as IPOXEMA;that of MEHEOX, MEOXEMA; that of DMHEOX, DMOXEMA, and so on.

(C) Copolymers are prepared from the various methacrylates produced inPart (B) hereof by the general procedure described in Example (IC)hereinabove with styrene (S), acrylonitrile (A), methyl methacrylate(MMA), butyl methacrylate (BMA).

Table I, in the first column gives the identification number (Id. No.)of nine copolymers conforming to the requirements of the invention thatboth hydrogens on the 2-carbon in the oxazolidine ring are substitutedby alkyl groups or an alkylene group and three comparison copolymers,two of them being identified by C1 and C2 in which the 2-position of theoxazolidine ring has 2 H atoms (SO) and one H (SI) respectively butotherwise is similar to copolymer Id. No. 5 just above these twocontrols. The third comparison copolymer is C3 to be compared with Id.No. 9. The second column gives the composition of the copolymers and themolar ratios of the components thereof. The numeral in () in this columnindicates the percentage of t-butylperacetate initiator used, based ontotal monomer weight. The next column lists the grams of comonomer usedand the particular comonomer by a letter symbol. The next column is thegrams of oxazolidine monomer and the particular one used by symbol (seethe key in the footnote). The next column indicates the grams of solventused; the next to last column gives the % solids in the product; and thelast column gives the amine titer in milliequivalents per gram (ME/g) ofthe product.

                                      TABLE I                                     __________________________________________________________________________    OXAZOLIDINE COPOLYMERS                                                                                        Product                                       Id.                                                                              Copolymer                                                                            Comonomer                                                                            Oxa-monomer                                                                           Solvent                                                                             %    Amine                                     No.                                                                              Code** g  Code**                                                                            g   Code**                                                                            g  Code**                                                                            Solids                                                                            Titer                                     __________________________________________________________________________    1  SM 2/1 (5)                                                                            91.7                                                                            S   100.0                                                                             M   127.8                                                                            CA  60  1.21                                      2  SM 3/1 (3)                                                                           137.5                                                                            S   100.0                                                                             M   158.3                                                                            PB  60  1.09                                      3  SM 3/1 (1)                                                                           137.5                                                                            S   100.0                                                                             M   158.3                                                                            PB  60  1.10                                      4  SM 5/1 (3)                                                                           229.3                                                                            S   100.0                                                                             M   219.5                                                                            PB  60  0.75                                      5  SD 3/1 (3)                                                                           316.0                                                                            S   215.0                                                                             D   758.6                                                                            XY  70  1.28                                      C1 SO 3/1 (3)                                                                           181.4                                                                            S   107.6                                                                             O   180.8                                                                            PB  60  0.77                                      C2 SI 3/1 (3)                                                                           234.0                                                                            S   170.5                                                                             I   253.5                                                                            PB  60  0.72                                      6  SAM 4/1/1                                                                            183.4                                                                             S* 100.0                                                                             M   204.5                                                                            PB  60  0.82                                         (3)                                                                        7  MMA/M 3/1                                                                            132.1                                                                            MMA 100.0                                                                             M   154.7                                                                            PB  60  1.02                                         (3)                                                                        8  BM 3/1 (2)                                                                           163.1                                                                            B    86.9                                                                             M   250.0                                                                            BC  50  0.558                                     9  BD 4/1 (2)                                                                           218.2                                                                            B    81.8                                                                             D   300.0                                                                            XY  50  0.640                                     C3 BO 3/1 (3)                                                                           426.0                                                                            B   194.7                                                                             O   611.0                                                                            XY  50  0.818                                     __________________________________________________________________________     *Plus 23.4 g. acrylonitrile (A)                                               **Symbols of codes                                                            S = styrene                                                                   A = acrylonitrile (in Id. No. 6)                                              B = butyl methacrylate                                                        MMA = methyl methacrylate                                                     M = MEOXEMA                                                                   D = DMOXEMA                                                                   O = OXEMA                                                                     I = IPOXEMA                                                                   CA = 2ethoxyethyl acetate                                                     BC = 2butoxyethanol-                                                          XY = xylene                                                                   ##STR6##                                                                 

(D) Coating compositions are prepared by mixing a 10-gram portion ofeach of the products listed in Table I identified therein with Id. Nos.1 through 5, C1, C2, and Id. Nos. 6 through 9 with an amount of 100%polyepoxide condensate, namely the commercial product Epon® 828 suchthat the ratio of NH/epoxy equivalents is 1:1. Also, 10 g of thesolution IIA (prepared in part A) of Example II) of polyfunctionalresinforming condensate (of2-ethyl3-(2-hydroxyethyl)-2-methyl-oxazolidine with theisocyanateterminated polyurethane prepolymer) is mixed with the samepolyepoxide to provide a 1:1 equivalency ratio of NH:epoxy.

Table II in column 1 lists the oxazolidine copolymer or resin by the Id.Nos. in Table I and by IIA for the lastmentioned product. The secondcolumn of Table II gives the amount of Epon 828 added. The third columnrefers to the properties of 5-mil wet film cast on Bonderite 1000 testpanels after 20 hours and the fourth column gives the methylenedichlorid (MDC) resistance of such films at 1 to 4 days. The next sevencolumns giv the appearance, hardness (Knoop Hardness No. KHN), andvarious resistance after 3 weeks ambient curing (70° F./50% relativehumidity) of suc films. The final colum gives the stability of thecoating solution when stored in the absence of moisture in closed cansor drums at 25° C

                                      TABLE II                                    __________________________________________________________________________    MIXTURE OF POLY(OXAZOLIDINE) AND EPON-828                                        g       MDC.sup.4                                                                          Properties on 3 weeks Ambient Curing                                                                      Stability.sup.3                   Id.                                                                              E-828                                                                             Prop..sup.3                                                                       Resist./                                                                           70° F./50% R.H.      (25° C.)                   No.                                                                              (100%)                                                                            20 Hrs.                                                                           Days Appear..sup.3                                                                      KHN MDC.sup.4                                                                         HAc.sup.5                                                                         HCl.sup.5                                                                        Tol..sup.5                                                                       MEOH.sup.5                                                                         of Mixture                        __________________________________________________________________________    1  2.42                                                                              C, H,                                                                             4/4  C, H, G,                                                                           19.0                                                                              4   4   4  3  2    C, F, 84                                 G, TF    TF                          days                              2  2.18                                                                              C, H,                                                                             4/4  C, H, G,                                                                           18.9                                                                              4   4   4  3  3    C, F, 84                                 G, TF    TF                          days                              3  2.20                                                                              C, H,                                                                             4/4  C, H, G,                                                                           18.4                                                                              4   4   4  3  3    C, F, 84                                 G, TF    TF                          days                              4  1.50                                                                              C, H,                                                                             4/4  C, H, G,                                                                           17.8                                                                              4   4   4  3  3    C, F, 84                                 G, TF    TF                          days                              5  2.56                                                                              C, H,                                                                             3/2  C, H, G,                                                                           19.6                                                                              4   4   4  3  3    C, F, 84                                 G, TF    TF                          days                              C1 1.61                                                                              C, H,                                                                             3/1  C, H, G,                                                                           16.3                                                                              3   4   4  3  2    Gel, <3 da.                              G, TF    TF                                                            C2 1.48                                                                              C, H,                                                                             3/1  C, H, G,                                                                           18.7                                                                              3   3   4  3  3    Gel, >30                                 G, TF    TF                          da., <84 da.                      6  1.64                                                                              C, H,                                                                             4/4  C, H, G,                                                                           17.4                                                                              4   4   4  3  3    C, F, 84 da.                             G, TF    TF                                                            7  2.04                                                                              C, H,                                                                             4/2  C, H, G,                                                                           15.6                                                                              4   1   1  3  3    "                                        G, TF    TF                                                            8  1.36                                                                              C, S,                                                                             4/4  C, St                                                                              6.68                                                                              3   1   4  2  2    "                                        G, St                                                                  9  1.28                                                                              C, S,                                                                             3/2  C, St                                                                              2.90                                                                              4   1   4  1  3    "                                        G, St                                                                  II-A                                                                             1.52                                                                              C, H,                                                                             T/4  C, T 10.7                                                                              4   1   4  1  3    "                                        G, TF                                                                  __________________________________________________________________________     .sup.3 C =  clear; H = hard; G = glossy; TF = tackfree, S = soft; St =        slight tack; T = tacky; F = fluid                                             .sup.4 Ratings in methylene dichloride (MDC)                                  4 = swelled with no soluble fraction                                          3 = swelled with slight amount of solubles                                    2 = swelled with significant solubles                                         1 = dissolved                                                                 .sup.5 10% aqueous HAc (acetic acid) with HCl, toluene and methanol; patc     tests, 2 hrs with acids, 1 hr with solvents                                   4 = no change                                                                 3 = slight softening                                                          2 = significant softening                                                     1 = delaminated or dissolved                                             

(E) Coating compositions are prepared by mixing 10-gram portions of theproducts listed in Table I identified with Id. No. 1 through 5, C1, C2,6 through 9, and C3, with an amount of a 75% solution in xylene of Epon®1001 that provides an NH/epoxy equivalent ratio of 1:1 or 1:2 asindicated in the second column of Table III. Also, a 10-gram portion ofsolution IIA and of solution IIIA are mixed with enough of thepolyepoxide to provide an NH/epoxy equivalent ratio of 1:1 and also anadditional 10-g portion of III-A is mixed with enough of the polyepoxideto provide an NH/epoxy equivalent ratio of 1:2. Table III gives theproperties of the test film prepared from the mixtures as in (D) aboveand the stability of the coating mixture. The same footnotes apply as inTable II.

The polyepoxide used in Part (E) and in Part (B) are of the classgenerally defined as the glycidyl polyethers of Bis-phenol A obtained byreacting 2,2-bis-(4-hydroxyphenyl)propane with epichlorohydrin asdescribed in U.S. Pat. No. 2,633,458.

                                      TABLE III                                   __________________________________________________________________________    MIXTURE OF POLY(OXAZOLIDINE) AND EPON 1001                                           g        MDC.sup.4                                                                        Properties on 3 weeks Ambient Curing                                                                      Stability.sup.3                Id.                                                                              NH/ E-1001                                                                            Prop..sup.3                                                                       RES/                                                                              70° F./50% R.H.      of Mixture                     No.                                                                              Epoxy                                                                             (75%)                                                                             20 Hrs                                                                            Day Appear..sup.3                                                                      KHN MDC.sup.4                                                                         HAc.sup.5                                                                         HCl.sup.5                                                                        Tol..sup.5                                                                       MEOH.sup.5                                                                         (25° C.)                __________________________________________________________________________    1  1/1 8.07                                                                              C, H,                                                                             4/4 C, H,                                                                              14.8                                                                              4   4   4  4  2    C, F; 84 da.                              G, TF   G, TF                                                      2  1/1 7.27                                                                              C, H,                                                                             4/4 C, H,                                                                              11.8                                                                              4   4   4  4  3    "                                         G, TF   G, TF                                                      2  1/2 14.54                                                                             C, H,                                                                             4/4 C, H,                                                                              9.27                                                                              4   4   4  4  2    "                                         G, TF   G, TF                                                      3  1/1 7.33                                                                              C, H,                                                                             4/4 C, H,                                                                              14.4                                                                              4   4   4  4  3    "                                         G, TF   G, TF                                                      4  1/1 5.00                                                                              C, H,                                                                             4/4 C, H,                                                                              14.4                                                                              4   4   4  4  2    "                                         G, TF   G, TF                                                      5  1/1 8.53                                                                              C, H,                                                                             3/2 C, H,                                                                              16.3                                                                              4   4   4  4  3    "                                         G, TF   G, TF                                                      5  1/2 17.16                                                                             C, H,                                                                             3/2 C, H,                                                                              16.5                                                                              4   4   4  4  3    "                                         G, TF   G, TF                                                      C1 1/1 5.36                                                                              C, H,                                                                             4/1 C, H,                                                                              17.7                                                                              3   4   4  4  3    gel, 3 da.                                G, TF   G, TF                                                      C2 1/1 4.93                                                                              C, H,                                                                             3/1 C, H,                                                                              21.0                                                                              3   4   1  4  3    gel, >30,                                 G, TF   G, TF                       <84 days                       6  1/1 5.47                                                                              C, H,                                                                             4/4 C, H,                                                                              17.5                                                                              4   4   4  4  3    C, F; 84 da.                              G, TF   G, TF                                                      7  1/1 6.80                                                                              C, H,                                                                             4/2 C, H,                                                                              13.4                                                                              4   1   4  4  3    "                                         G, TF   G, TF                                                      7  1/2 13.60                                                                             C, H,                                                                             3/4 C, H,                                                                              10.7                                                                              3   4   4  4  3    "                                         G, TF   G, TF                                                      8  1/1 3.72                                                                              C, H,                                                                             3/2 C, H,                                                                              9.68                                                                              4   4   4  4  3    "                                         G, TF   G, TF                                                      9  1/1 4.27                                                                              C, H,                                                                             3/2 C, H,                                                                              7.42                                                                              4   4   4  1  1    "                                         G, TF   G, TF                                                      C3 1/1 5.45                                                                              C, H,                                                                             1/4 C, H,                                                                              15.3                                                                              3   3   4  2  2    gel >30,                                  G, TF   G, TF                       <84 days                       II-A                                                                             1/1 2.85                                                                              C, T                                                                              T/4 C,S,TF                                                                             *   4   1   4  1  2    gel >30,                                                                      <84 days                       III-                                                                             1/1 5.40                                                                              C, H,                                                                             4/4 C, H,                                                                              4.54                                                                              4   1   1  3  3    C,F; 84 das.                   A          G, TF   G, TF                                                      III-                                                                             1/2 10.80                                                                             C, H,                                                                             4/4 C, H,                                                                              11.8                                                                              4   1   1  3  3    "                              A          G, TF   G, TF                                                      __________________________________________________________________________     *Rubbery; Other footnotes are same as in Table II                        

(F) Coating compositions are prepared with 10-gram portions ofoxazolidine copolymer Id. Nos. 1 through 9 of Table I by mixing eachportion with a diglycidyl ether condensate of Bis-phenol A which hasbeen hydrogenated to saturate the aromatic groups. The polyepoxide usedtherein may therefore be properly designated a glycidyl polyether of2,2-bis-(4-hydroxycyclohexyl)propane. This saturated polyepoxide ispreferred for reasons of durability against ultraviolet light. An amountof the saturated polyepoxide thereby obtained is added to each of the 9copolymers to provide an equivalency ratio of 1:1 of NH/epoxy in themixture. A 50% solution, in xylene or Propasol B, of a polyepoxide ofthe type available under the trademark Eponex® 151.1 is used. Acomparison mixture of a 10-gram portion of a commercially availablecondensation product of a long-chain fatty acid and an aliphaticpolyamine, identified as V in Table IV, that has been used as apolyepoxy resin curing agent is provided.

The mixtures are coated, stored, and tested in the same way as themixtures and films thereof were tested in (D) and (E) hereinabove. Also,the same footnotes as in Table II apply to the tabulation of results inTable IV following.

The present invention is the result of the discovery that(poly)functional oxazolidines in which both hydrogen atom of theII-position carbon in the ring is substituted by alkyl groups or analkylene group serve as latent polyepoxide curing agents andresin-forming polyepoxides can be mixed with the latent curing agent andstored in the absence of moisture for months without noticeable changeor reaction but that on formation of films of the composition andexposure thereof to moisture, even ambient air having a relativehumidity of at least 20%, and preferably at least 50%, providesreasonably rapid curing to form hard, high performance coatings. Incontrast, mixtures of a resin-forming polyepoxide with (poly)functionaloxazolidines in which neither or only one of the hydrogen atoms on the2-position carbon is replaced with alkyl or alkylene groups lackstability on storage; even in the absence of moisture such anoxazolidine undergoes reaction directly with the polyepoxide as atertiary amine that causes gelation. Apparently the 2,2-dialkyl or2,2-alkylene oxazolinyl rings of Formula IA are in effect stericallyhindered and must be hydrolyzed by moisture to produce an hydroxyalkylgroup of formula IB supra to cure the polyepoxide.

                                      TABLE IV                                    __________________________________________________________________________    MIXTURE OF POLY(OXAZOLIDINE) AND EPONEX®  151.1                              g        MDC.sup.4                                                                          Properties on 3 weeks Ambient Curing                                                                      Stability.sup.3                  Id.                                                                              E-151.1                                                                           Prop..sup.3                                                                        Resist./                                                                           70° F./50% R.H.      (25° C.)                  No.                                                                              (50%)                                                                             20 Hrs.                                                                            Days Appear..sup.3                                                                      KHN MDC.sup.4                                                                         HAc.sup.5                                                                         HCl.sup.5                                                                        Tol..sup.5                                                                       MEOH.sup.5                                                                         of Mixture                       __________________________________________________________________________    1  2.84                                                                              C, H,                                                                              4/4  C, H, G                                                                            15.7                                                                              4   1   2  3  3    C, F;                                   G, TF                                 84 days                          2  2.56                                                                              C, H,                                                                              4/4  "    15.6                                                                              4   3   4  3  3    C, F;                                   G, TF                                 84 days                          3  2.59                                                                              C, H,                                                                              4/4  "    16.7                                                                              4   4   4  3  3    C, F;                                   G, TF                                 84 days                          4  1.76                                                                              C, H 4/4  "    13.9                                                                              4   4   4  1  3    C, F,                                   G, TF                                 84 days                          5  6.01                                                                              C, H,                                                                              4/4  "    10.9                                                                              4   1   4  1  2    C, F;                                   G, TF                                 84 days                          6  1.93                                                                              C, H,                                                                              4/4  "    1.73                                                                              4   4   4  3  3    C, F;                                   G, TF                                 84 days                          7  2.40                                                                              C, H,                                                                              4/4  "    14.4                                                                              4   1   1  3  3    C, F;                                   G, TF                                 84 days                          8  2.62                                                                              C, G, T                                                                            1/2  C, S, G                                                                            2.40                                                                              4   1   2  1  3    C, F;                                                                         84 days                          9  3.00                                                                              "    1/2  "    1.80                                                                              4   1   4  1  3    C, F; -           84 days        V  1.44                                                                              "    4/4  H, T,                                                                              7.19                                                                              4   1   1  4  4    gel <8 hrs.                                       SS*                                                          __________________________________________________________________________     *SS = surface spue                                                       

EXAMPLE VII Water-Reduced Coatings

(A) To 689 g of a solution containing 66.6% polymer solids of acopolymer of styrene and MEOXEMA (3:1 molar ratio) in xylene, having anamine titer of 1.20 ME/g of solution, is added 165.4 of Epon 828 resin.The resulting solution is heated to 100° C. and xylene is removed bydistillation under reduced pressure until the resinous distillationresidue contains about 93-4% polymer solids. The resinous distillationresidue is then diluted with 111.8 g of methyl n-propyl ketone to obtaina mixture containing 80% polymer solids.

To 50 g of this diluted mixture there is added 1 g of phenoxyethanol and1 g of Capcure® 65 emulsifier followed by the further addition of 16.7 gof water, dropwise and while stirring rapidly, thereby obtaining awater-reduced coating emulsion.

This emulsion is then cast as a 5 mil wet film coating on Bonderite 1000immediately after preparation and again after the emulsion has beenallowed to stand 5 hours at ambient conditions. Both of the resultingcoatings are white when freshly cast but become clear after standing 30minutes at ambient conditions. After curing 7 days at ambientconditions, the coatings are swelled, but not dissolved, by methylenechloride, which property indicates that crosslinking has occurred.

(B) To 189 g of a solution of a copolymer of isobutyl methacrylate andMEOXEMA (3:1 molar ratio) in xylene, having an amine titer of 1.16 ME/gof solution, is added 51.5 g of Eponex® 151.1 resin (an aliphaticepoxide resin). The resulting solution is heated to about 100° C. andxylene is removed by distillation under reduced pressure. The resinousdistillation residue is then dissolved in 28.2 g of methyl n-propylketone. To 50 g of this solution there is added 2.0 g of phenoxyethanoland 1.5 g of Capcure® 65 emulsifier followed by the further addition31.0 g of water, dropwise and while stirring rapidly, thereby obtaininga water-reduced coating emulsion.

This emulsion is then cast as a 7 mil wet film coating on Bonderite®1000 panels. After drying for 30 minutes at ambient temperature, thecoating is clear (transparent). After curing for both 30 minutes and for24 hours at ambient temperature the coating is swelled, but notdissolved, by methylene chloride, which property indicates thatcrosslinking has occurred.

Preliminary outdoor durability data indicates that the coating of part(B) of this example possesses more prolonged outdoor durability than dosimilar coatings derived from photochemically reactive aromaticcomponents such as styrene and bis-phenol A.

EXAMPLE VIII Preparation of Adhesive Composition (A) Amine Copolymer

To 150.0 g of xylene, heated at 105° C. with stirring and maintainedunder a nitrogen atmosphere, is added dropwise over a period of 4 hoursa solution of 323.0 g of isodecyl methacrylate, 27.05 g of MEXOEMA and10.50 g of t-butyl peroctoate. When the addition is complete, anadditional charge of 1.05 g of t-butyl peroctoate is added to thestirred polymerization reaction mixture and the temperature ismaintained at 105° C. for 30 minutes before cooling the product.

The product is a clear, light yellow solution, contains an amine titerof 0.21 ME/g and has a Mw of 27,9000 and a Mn of 7360 (determined by gelpermeation chromatography).

(B) Adhesive Composition

To 10.0 g of the solution obtained in Part (A) above is added 0.42 g ofEpon® 828. The resulting solution is coated as a 2 mil wet film onBonderite® 1000 panels. After drying overnight at ambient temperature, avery tacky and adhesive coating is obtained. The coated film is suitablefor use as a pressure sensitive adhesive and adheres to nylon, propyleneand polyethylene terephthalate films. The coating is then stored in astoppered vial at room temperature. After 30 days of storage, theappearance of the solution is unchanged from its initial appearance.

We claim:
 1. A hydrocurable composition adapted to be used for coating,impregnating, or adhesive purposes at ambient conditions of temperatureand relative humidity comprising an anhydrous mixture of (1) aresin-forming polyepoxide containing at least two vic-epoxy groups and(2) a polyfunctional compound containing at least two cyclicoxazolidinyl groups of the formula ##STR7## wherein m is 2 or 3, andR¹and R² are either separate alkyl groups, each having at least one carbonatom, or are joined directly together to form an alkylene group of 4 or5 carbon atoms, the compound (2) containing no other amine nitrogengroups, and the amount of (2) being sufficient to provide at least aboutone equivalent of epoxy group for each equivalent of amine in (1), thecomposition, in the absence of moisture, being stable for months.
 2. Acomposition according to claim 1 wherein the polyfunctional compound (2)is a condensation product of (a) a compound having the cyclic group ofthe formula IA as defined therein with a hydroxyalkyl group attached tothe N atom thereof with (b) a polycarboxylic acid or a polyisocyanate,or (2) is a transesterification product of (a) with a polyester of apolycarboxylic acid.
 3. A composition according to claim 1 wherein thepolyfunctional compound (2) is a vinyl addition copolymer ofmonoethylenically unsaturated monomers having a group H₂ C═C< comprisingat least one monomer selected from the acrylic acid or methacrylic acidesters of a hydroxy(C₂ -C₃)alkyl group substituted on the N atom of thecyclic group of formula IA as defined therein.
 4. A compositionaccording to claim 3 wherein the copolymer also comprises at least onemonomer selected from styrene, vinyltoluene, acrylonitrile, and C₁ -C₁₈alkyl esters of acrylic or methacrylic acid.
 5. A composition accordingto claim 1 wherein m is
 2. 6. A composition according to claim 3 whereinthe compound (2) is a copolymer of2,2-dimethyl-3-(meth)acryloxyethyloxazolidine and at least one monomerselected from styrene, vinyltoluene, acrylonitrile, and C₁ -C₁₈ alkylesters of acrylic or methacrylic acid.
 7. A composition according toclaim 3 wherein the compound (2) is a copolymer of2-ethyl-3-(meth)acryloxyethyl-2-methyl-oxazolidine and at least onemonomer selected from styrene, vinyltoluene, acrylonitrile, and C₁ -C₁₈alkyl esters of acrylic or methacrylic acid.
 8. A composition accordingto claim 3 wherein the compound (2) is a copolymer of2-n-propyl-3-(meth)acryloxyethyl-2-methyl-oxazolidine and at least onemonomer selected from styrene, vinyltoluene, acrylonitrile, and C₁ -C₁₈alkyl esters of acrylic or methacrylic acid.
 9. A composition accordingto claim 1 wherein the polyepoxide (1) is a glycidyl polyether of2,2-bis(4-hydroxyphenyl)propane.
 10. A composition according to claim 1wherein the polyepoxide (1) is a glycidyl polyether of2,2-bis(4-hydroxycyclohexyl)propane.
 11. A method for making and using ahydrocurable polyepoxide composition containing a latent curing agentwhich comprises mixing, in the absence of moisture, (1) an essentiallyanhydrous resin-forming polyepoxide containing at least two vic-epoxygroups and (2) a polyfunctional compound, as a latent curing agent forthe polyepoxide, containing at least two cyclic oxazolidinyl groups asdefined in claim 1 in the relative proportions stated therein,optionally mixing any additional anhydrous ingredients that are inert to(1) and (2), storing the composition in tightly closed containers thatserve to exclude water in liquid or vapor form, as in humid or moistambient air, until the time of use, or transport to the place of use,and subsequently applying the composition by spreading a film of it overor on a surface to be coated, impregnated, or adhesively joined toanother surface, exposing the film, during or after its formation, toambient moist air at ambient temperature and having a relative humidityof at least 20% to effect curing of the polyepoxide by reaction with thesecondary amine formed by hydrolytic splitting of the oxazolidinyl ringin the latent curing agent (2).